Your outside lines are usually on small planer boards and you would like them to be deeper in the summer months. If you look at the back of the boat, you would like to have your lines like a V so the ones next to the boat are the deepest and the out side are the most shallow. This way if you get a fish you can fight it over the top of the lines and get it to the center of the wake. The small planer boards allow you to get the line away from the boat but still get down to around 40' or so with your spoons. That is the reason for steel and leadcore lines. I have used a dipsy diver with steel and hit bottom in 100' of water. It hit a couple of times until I straightened the boat and then caught me a 18lb Lake Trout. It was harder then hell to get it into the net when I was fishing all by myself. Did not really matter cause I released it any ways.